Work on Fiends

- Fix compatibility problems between PnP Fiends and SCS >= 22.
  The old code required an opcode 177 with the vanilla EFF, but the
  fiend-summoning spells don't have that with new SCS.
- Refactor code
Correct typo
Fix cosmetic compatibility issue with Spell Revisions
Dual-wielding for Arcanaloths
Polish revised fiend summoning
Generalise the Yugoloth scripts
Changed BAF as a result of the reorganisation
Changed Shadow Fiend BAFs as a result of changes long ago
Scripts for SCS-summoned Yugoloths
Change targeting of Secret Word
Ignore ssl/baf/
Fix line endings
Ignore TAGS file
Improve compatibility and integration with SCS
Proper cleric version of Gate for Revised Fiend Summoning
SCS fiends don't cause friendly fire
Changed BAF due to commit 5c6fc75c57588127aa29b47d687ae2730f28fbd5
make_baf.pl can make the new SCS-compliant Yugoloth BAFs
New BAFs for SCS-compliant Yugoloth